THE MAXILLA 



57 



The anterior palatine fossa is situated in the meso-palatine suture near its 

 anterior termination. In its typical form the fossa contains four i)assages: two are 

 small and dis])()sed one l)ehind the other exactly in the suture; these are the 

 foramina of Scarpa for the naso-palatine nerves, the left nerve emerging from the 

 anterior foramen. The lateral and larger orifices diverge to open on each side of the 

 crest. They are called Stenson's canals, and lodge recesses of the nasal mucous 

 membrane and remnants of Jacobson's organs. 



Th(^ alveolar ridge forms the outer limit of this surface; it is creseentic in 

 shape, spongy in texture, and presents cavities in which teeth are lodged. When 

 the teeth are complete in number, eight cavities are i)resent; of these the pit for 

 th(! canine tootli is the deepest, those for the molars are the widest and present 

 subdivisions. Along the outer aspect of the alveolar l)order the buccinator arises as 

 far forwards as the first molar tooth. 



The nasal process is somewhat triangular, rising vertically from the nasal 

 angle of the maxilla. Its outer surface gives attachment to the orbicularis palpe- 

 brannn, the tendo oculi, and the levator labii superioris alseque nasi. The internal 

 surface forms one of the lateral boundaries of the nasal fossa. Superiorly it 

 articulates with the frontal; below this is the superior turbinated crest for articu- 

 lation with the middle turliinal. The space between this and the inferior turbin- 

 ated crest forms ])art of the middle meatus. The anteri(jr l)order articulates with 

 the nasal l)one; the posterior is thick and vertically grooved to form {)art of the 



Fig. (iii. — Thk Maxili.a at Birth. 



PftEMAXILLARY P3RTI0N 



Outer view. 



Inferior view. 



Inner view. 



nasal duct. The inner margin of this groove articulates with tlie lachrymal Ixme. 

 The point where the outer margin of the groove joins the orl)ital plate is indicated 

 by the lachrymal tubercle. 



The malar process is rough and triangular, and forms the summit (jf the 

 ridge of bone separating the facial and zygomatic surfaces. It articulates with the 

 malar bone, and from its inferior angle a few fibres of the ina^^neter take origin. 



Tlie antrum or maxillary sinus, as the air-chamber occupving the body of the 

 bone is called, is somewhat pyramidal in shape; the base lieing represented by the 

 nasal or internal surface, ancl the apex corresponding to the malar process. In 

 addition to these it has four walls: the superior is formed I)y the orI)ital plate, and 

 the inferior by the alveolar ridge. The anterior wall corres})onds to the facial sur- 

 face of the maxilla, and the posterior is formed by the zygomatic surface. Tin- 

 inner l^oundary or base presents a very irregular oritice at its posterior })art; this 

 is partially filled in by the vertical plate of the palate bone, the uncinate process of 

 the ethmoid, the maxillary process of the inferior turbinal, and a small portion of 

 the lachrymal bone. Even when these bones are in situ, the nasal oritice is very 

 irregular in shape, and requires the mucous membrane to form the definite rounded 

 aperture (or apertures, for they are often multi])le) known as the opening of the 

 antrum. The cavity of the antrum varies considerably in size and shai)e. In the 

 young, it is small and the walls are thick: as life advances, the antrum enlarges 

 at the expense of its walls, and in old age they are often of extreme tenuity; 

 occasionally the cavity extends into the suljstance of the malar bone. The Hoor of 



